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02 Dmax 2500 6.6l - Black smoke

Matt Bachand

Matt Bachand

Depends on the 6.5
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Location
Worcester, MA
A friend of mine called me asking me about a customers Duramax.

Here's what I have- which isn't ideal, I know.

02 Duramax 6.6, around 100,000 miles

It recently had a 'sensor' replaced costing around 700 dollars, and found out there injectors underwarranty that could have been replaced but they found dirty fuel filter so warranty is out, and they want a few thousand for injector job.

It has plenty of power, just blows black smoke.

I told him to check air intake for restriction as well as air cleaner and turbo for fuction.

Anything comes to mind to have him check?

Thanks guys!
 
What type of turbo do these have? Wastegate? What controls boost? From what I've gathering it sounds like he either doesn't have enough boost, or the computer is dumping in too much fuel.

It's a stock truck.
 
Check the intercooler tube over by the power steering lines to see if it has rubbed through. The LB7 uses a wastegated turbo and the ECM limits fueling by measuring the airflow via teh MAF sensor at the airbox. If the intercooler tubing gets a hole in it(very common at the spot I mentioned), the ECM will see airflow but the engine won't actually get it.
 
Thanks guys.

He says the IC Checks out, but I told him be sure. To me it most definately sounds like a lack of air issue.

It throws no codes, and has 188,000 miles not 100,000 as I said.

There was some sort of recall on the injectors???? They refused it due to fuel filter dirty.

What is the best way to check the IC for leaks besides visual?

Is there ANYTHING else that could make it run rich w/black smoke without coding?

Seems to be an injector thought stuck in the owners head.

Any injector issue would probably result in skipping and/or white smoke?
 
Injectors stuck open will result in a no start when hot normally, and sticking one will pour out blue smoke or white smoke normally. Black smoke is very hard to get on a stock truck unless there is a massive boost leak somewhere. I still think he has a boost problem. Even if his MAF sensor was reading the max it would eventually clear the black smoke up once the turbo lights off. As for a recall on teh injectors, there never was. There was a special policy on them regarding an extended warranty for a specific failure. It COULD be injectors, but it doesn't sound like it. Could POSSIBLY be a rail pressure sensor that is reading lower than actual rail pressure which would cause it to black smoke heavily. Needs to be hooked up to a tech 2 or EFILIVE and see what rail pressure, pulsewidth, MAF readings, and boost are doing. I think you'll find that the MAF is going up and not the boost. Or if the truck is tuned it could just be one of the infamous early OS gremlins. Still sounds to me like a boost leak which is easy enough to find out if he has a boost guage or hooks up a scanner and sees what the boost is doing.
 
Stuck injector is a no hot start, and or cylinder wall wash down. Meaning the oil will be full of fuel. Generally a bad injector will produce blue smoke, it is an air delivery issue. have you checked the waste gate?? Possibly stuck open
 
If this is a CARB emissions truck it will have the VVT and a vane position sensor that could possibly be the culprit.
 
well the answer to this problem will likly fix mine to. Mine had a knock in it and was getting fuel in the oil. i replaced the pass. side injectors and now it sounds good but not a very linear power curve and to much smoke under throttle non at idle seems like a boost problem
 
well i was thinking about this all and went and drove it around the block again. i must have a boost leak, if u get on it u can hear a strong hissing noise coming from what sounds like the drivers lower corner which would indicate maybe a leak on the intercooler boot.
this wear issue with power steering lines, is that through the boot or through the metal tube??
 
tireguy said:
this wear issue with power steering lines, is that through the boot or through the metal tube??
Click to expand...

It deals with the metal tube where the power steering lines pass by it at the pump. I know I welded mine up when I did the engine swap as it was almost worn through.
 
Matt Bachand said:
A friend of mine called me asking me about a customers Duramax.

Here's what I have- which isn't ideal, I know.

02 Duramax 6.6, around 100,000 miles

It recently had a 'sensor' replaced costing around 700 dollars, and found out there injectors underwarranty that could have been replaced but they found dirty fuel filter so warranty is out, and they want a few thousand for injector job.

It has plenty of power, just blows black smoke.

I told him to check air intake for restriction as well as air cleaner and turbo for fuction.

Anything comes to mind to have him check?

Thanks guys!
Click to expand...

I have a problem with the above bolded statement. I'm assuming the stealership said this? Though this defiantly seems like an air related issue if the fuel filter was "dirty" then there would most certainly be a LACK of power (not enough fuel). Excessive smoke like you are describing shows that the fuel system is working fine. Someone over there is pulling your buddys leg. See if you can get the stealership to provide you a paper copy of the injector balance rates, pulse width and whatnot like Ferminator said and post it up here so we can get an idea as to what the fuel system is doing.

Also, what is this "sensor" that was replaced?
 
hi i'm mike and new to the truck stop.i have a a duramax 6.6. i have an edge programmer and some of the injector balances are out of spec.i also use coolant about 1/2 gallon in 75 mile trip. i don't think it's a head gasket.the injectors have been replaced before and i wonder if the cups could be leaking. i have read that that the cups can leak coolant.wondering if maybe they need resealed.gonna start the job soon.would appreciate and helpful ideas of how to proceed.
 
Cups can leak, yes, but they normally only leak shortly after an injector job. If it's been awhile since the injectors were done, then it is most likely a head gasket. Another test is to pressurize the cooling system and keep it pressurized for say 6 hours, pull the glow plugs out, then spin the engine over. If coolant shoots out it is generally cups leaking, if no coolant comes out it is generally head gaskets.
 
THEFERMANATOR said:
Cups can leak, yes, but they normally only leak shortly after an injector job. If it's been awhile since the injectors were done, then it is most likely a head gasket. Another test is to pressurize the cooling system and keep it pressurized for say 6 hours, pull the glow plugs out, then spin the engine over. If coolant shoots out it is generally cups leaking, if no coolant comes out it is generally head gaskets.
Click to expand...
thank you for you're help.i will pressurize it and see where i'm at.
 
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